Differential and thrust washer therefor

ABSTRACT

A thrust washer and a differential containing a thrust washer. The differential has a housing, a spider with a plurality of spider arms, and one or more spider gears. The thrust washer includes a body comprising an annular shape having a width configured to approximately match a width of the one or more spider gears and further configured to a have a slope along the width configured to conform with an inner diameter of the housing and at least one engagement mechanism to engage with at least two of the plurality of spider arms to engage the thrust washer with the spider to approximately prevent the thrust washer from rotating relative to the housing when the thrust washer is installed in the differential.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/381,697, filed Jul. 21, 2021, which is a continuation of PCT PatentApplication No. PCT/CA2020/050068, filed Jan. 21, 2020, which claimspriority to and the benefit of U.S. Provisional Patent Application62/794,895 filed Jan. 21, 2019, the content of which are herebyincorporated herein by reference.

TECHNICAL FIELD

This document relates to a differential and a thrust washer therefor,and, in particular, to a thrust washer for use with spider gears in adifferential.

BACKGROUND

Many types of vehicles use a differential to control the distribution ofdrive power to drive wheels and the like. In a typical differential, oneor more pinion gears (sometimes called “pinions”, “spider gears” or“planetary gears”) are connected with a ring/driving gear via a spiderand configured to interact with side gears to provide a variabledistribution of power to drive wheels. The side gears each drive an axlewhich supports the drive wheels of the vehicle. The side gears and thespider gears are supported in a housing. In order to protect the housingand the spider gears, the differential will generally also include oneor more washers, generally called thrust washers, located between thespider gears and the housing. Conventional thrust washers are designedin various ways.

FIG. 1 illustrates several types of conventional thrust washers. FIG. 1Ashows a flat or somewhat concave thrust washer. This type of thrustwasher is typically mounted on the spider and can rotate relative to thepinion as well as the housing. In this case, a thrust washer materialthat has dry lubricating properties (for example: bronze) may be able tospin against the housing without causing a large amount of damage.However, this type of design may result in a failure of the washer orthe housing due to contamination and fluid film issues. For example,since the differential motion only occurs for limited periods of timeand does not spin sufficiently to build a proper lubricant film, thecoefficients of friction can be unpredictable. In addition, smallparticles in the oil that are larger in diameter than the lubricant filmcan rapidly increase the coefficient of friction between the gear andwasher causing the majority of the sliding to occur between the thrustwasher and housing. With the housing being soft, wear can occur quiteeasily and increases the contamination in the system

FIG. 1B is a flat or somewhat concave thrust washer that has a tab/flapor the like which is intended to lock the washer in relation to thehousing and thus, prevent rotation of the washer in relation to thehousing. In particular, the differential housing is typically made froma softer material (ductile or grey iron) for manufacturability and costwhile the spider gear is made from hardened steel and capable ofwithstanding high sliding without experiencing noticeable wear. Sincethe housing is softer than the spider gear, the housing is generally notable to withstand the sliding action as well and can often experiencewear that can result in a malfunction. The use of locking tabs can leadto stress concentrations and a large increase in friction can cause thetabs to fracture. An increase in friction can be due to contaminates inthe oil in the differential, particularly when the contaminates arelarger in diameter than the fluid film.

FIG. 1C is a flat or somewhat concave thrust washer having a texturedsurface. The textured surface runs against the spider gear and isdesigned to reduce friction against the gear (by providing a lowercoefficient of friction). The differential housing which is rougher hasa higher coefficient of friction and is intended to help lock the thrustwasher against the housing to prevent rotation.

FIG. 1D is a flat or somewhat concave thrust washer having both atextured surface and tabs for locking the washer in relation to thehousing. This is intended to incorporate the elements of the thrustwashers in FIGS. 1B and 1C together.

Even with thrust washers having locking mechanisms of the type describedabove there can be an issue with housing or washer wear or failure dueto the high forces encountered in the differential during operation. Assuch, there is a need for an improved differential and thrust washer foruse in differentials that provides better protection for the mechanismand a longer life for the differential.

SUMMARY

According to an aspect herein there is provided a thrust washer for adifferential having a housing and an assembly of a spider and one ormore spider gears, the thrust washer including: a body having an annularshape and a width configured to approximately match with a widthof/cover the one or more spider gears and further configured to engagewith the spider to prevent or reduce the thrust washer from rotatingrelative to the housing when the thrust washer is installed in thedifferential.

In some cases, the spider includes at least one spider arm and thethrust washer includes at least one engagement mechanism having a sizeand a shape to engage with an outer diameter of the at least one arm toengage the thrust washer with the spider. In some cases, the at leastone spider arm includes four arms, the at least one engagement mechanismincludes four apertures, and each of the four apertures are positionedand oriented to engage a respective one of the four arms when the thrustwasher is installed in the differential.

In some cases, the thrust washer includes a slope along the widthconfigured to conform with an inner diameter of the housing. In somecases, the slope along the width also conforms to a shape of the spidergears.

In some cases, the thrust washer includes a first portion and a secondportion, and the first portion and the second portion are configured toassemble around the spider and the spider gears. In some cases, theslope is configured to engage with the housing to reduce separation ofthe first portion and the second portion. In some cases, the firstportion and the second portion are configured to provide a gap betweenthe first portion and the second portion when assembled to allow theflow of debris or the like. In some cases, the thrust washer has acontinuous ring shape. In some cases, the thrust washer includes a gapacross the width of the thrust washer. In some cases, the thrust washeris a single contiguous body.

According to an aspect herein there is provided a differentialincluding: a housing; a spider and one or more spider gears; at leasttwo side gears positioned and oriented to engage the one or more spidergears within the housing; and a thrust washer positioned between thehousing and the one or more spider gears, the thrust washer including: abody having an annular shape and a width configured to approximatelycover the one or more spider gears and and further configured to engagewith the spider to prevent the thrust washer from rotating relative tothe housing when the thrust washer is installed in the differential.

In some cases, the spider comprises at least one spider arm and whereinthe thrust washer includes at least one engagement mechanism having asize and a shape to engage with an outer diameter of the at least onespider arm to engage the thrust washer with the spider. In some cases,the at least one spider arm includes four arms, the at least oneengagement mechanism includes four apertures, and each of the fourapertures are positioned and oriented to engage a respective one of thefour arms when the thrust washer is installed in the differential.

In some cases, the thrust washer further includes a slope along thewidth configured to conform with an inner diameter of the housing. Insome cases, the slope along the width also conforms to a shape of thespider gears.

In some cases, the thrust washer includes a first portion and a secondportion, and the first portion and the second portion are configured toassemble around the spider and the spider gears. In some cases, theslope is configured to engage with the housing to reduce separation ofthe first portion and the second portion. In some cases, the firstportion and the second portion are configured to provide a gap betweenthe first portion and the second portion to allow the flow of debris orthe like.

In some cases, the thrust washer has a continuous ring shape. In somecases, the thrust washer includes a gap across the width of the thrustwasher. In some cases, the thrust washer is a single contiguous body.

Other aspects and features of the thrust washer will become apparent, tothose ordinarily skilled in the art, upon review of the followingdescription of some exemplary embodiments.

The drawings included herewith are for illustrating various examples ofarticles, methods, and apparatuses of the present specification and arenot intended to limit the scope of what is taught in any way.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D show examples of conventional thrust washers;

FIG. 2 is a perspective exploded view of a differential according to anembodiment herein;

FIG. 3 is a perspective side view of the differential of FIG. 2 ;

FIG. 4 is a perspective exploded view of a thrust washer according to anembodiment herein, combined with a spider and spider gears;

FIG. 5A is a top view of a thrust washer according to an embodimentherein, combined with a spider and spider gears;

FIG. 5B is a side view of a thrust washer according to an embodimentherein, combined with a spider and spider gears;

FIG. 6 is a sectional view of the differential of FIG. 2 , illustratingthe thrust washer of FIG. 4 within the differential housing but withinternal gears hidden;

FIG. 7 is a sectional perspective view of FIG. 6 ;

FIG. 8 is a sectional view of the differential of FIG. 2 , illustratingthe thrust washer of FIG. 4 within the differential housing but withgears shown.

FIG. 9 is a perspective view of a conventional thrust washer in aconventional differential housing with the gears hidden;

FIG. 10 is a perspective view illustrating a comparison between aportion of a thrust washer according to an embodiment herein with aconventional thrust washer such as that of FIG. 9 ;

FIG. 11A is a perspective view a thrust washer according to anembodiment herein when positioned in a differential housing;

FIG. 11B illustrates the flow of oil within a differential housingaccording to the embodiment of FIG. 11A;

FIG. 12 illustrates a thrust washer according to an embodiment herein;and

FIG. 13 illustrates a thrust washer according to another embodimentherein;

FIG. 14 illustrates a thrust washer according to another embodimentherein, combined with a spider and spider gears;

FIG. 15 is a perspective exploded view of a thrust washer such as thatin FIG. 14 .

DETAILED DESCRIPTION

Various systems, apparatuses or methods will be described herein toprovide example embodiment(s). No embodiment described below is intendedto limit any claimed invention. The claims are not limited to systems,apparatuses or methods having all of the features of any one embodimentor to features common to multiple or all of the embodiments describedherein. A claim may include features taken from any embodiment or aselection of embodiments as would be understood by one of skill in theart. The applicants, inventors or owners reserve all rights that theymay have in any invention disclosed herein, for example the right toclaim such an invention in a continuing application and do not intend toabandon, disclaim or dedicate to the public any such invention by itsdisclosure in this document.

FIG. 2 is a perspective exploded view of a differential 200 according toan embodiment herein. FIG. 3 is a side exploded view of the differential200 of FIG. 2 . The differential 200 includes: a housing 210, two sidegears 215, a spider (cross) 220, four spider (pinion) gears 225, and athrust washer 230. The housing 210 includes first housing portion 210 aand second housing portion 210 b, which may be combined to form housing210. The thrust washer 230 includes first thrust washer portion 230 aand second thrust washer portion 230 b, which may be combined to formthrust washer 230. The spider 220 includes four arms (e.g. stub shaftsor posts) 222.

The side gears 215 are supported in the housing 210. The spider gears225 are each mounted on one of the arms 222 (i.e. stub shafts or posts)of the spider 220. In other words, the spider gears 225 and the spider220 form a spider gear assembly. The spider 220 is also supported in thehousing 210 such that the spider gears 225 mesh with the side gears 215.The thrust washer 230 is provided such that the body of the thrustwasher engages with the spider 220 and is located between the spidergears 225 and the housing 210.

FIG. 4 is a perspective exploded view of an embodiment of the thrustwasher 230 when paired with the spider 220 and spider gears 225 of thedifferential 200 of FIG. 2 . FIGS. 5A and 5B are top and front views,respectively of the embodiment of the differential 200 of FIG. 4 . Asshown, the differential 200 includes a thrust washer 230 having a bodyformed of two halves or portions, a first thrust washer portion 230 aand a second thrust washer portion 230 b. The first thrust washerportion 230 a is generally a mirror image of the second thrust washerportion 230 b and has a ring/annular shape. In particular, in thisembodiment, each of first thrust washer portion 230 a and second thrustwasher portion 230 b is a continuous ring/cylinder but this is notrequired (as described below). In other words, in some embodiments thethrust washer has an annular shape and is also a discontinuousring/cylinder. Each of first thrust washer portion 230 a and secondthrust washer portion 230 b has a diameter 275 that is configured to bewide enough to enclose all of the spider gears 225 within the thrustwasher 230. Each of first thrust washer portion 230 a and second thrustwasher portion 230 b has a width 270 that is configured to be wideenough to match a width of/cover the spider gears 225 and thus separatethe spider gears 225 from the housing 210 and thereby protect thehousing 210 from the spider gears 225, for example, to prevent or reducewear on the housing 210 caused by the spider gears 225. In some cases,the thrust washer 230 may have a slope or curvature along its width 270to conform to the shape of the housing inner diameter (ID) and/or theshape of the spider gears 225.

Each spider gear 225 includes an outer edge (i.e. back face) 227. Somelocations of the outer edge 227 of spider gears 225 are denoted in FIG.4 , while additional examples of outer edges 227 have been omitted forclarity. Each of first thrust washer portion 230 a and second thrustwasher portion 230 b includes one or more indentations (e.g. cutouts)232 positioned on a first edge 280 to allow them to engage with thespider 220 in such a way that the thrust washer covers substantially allof the outer edges 227 of the spider gears 225 when the differential 200is assembled. The one or more indentations 232 of the first thrustwasher portion 230 a and the one or more indentations 232 of the secondthrust washer portion 230 b combine to form one or more engagementmechanisms/connectors/apertures of the thrust washer 230. In otherwords, the thrust washer 230 includes one or more engagementmechanism/connectors/apertures that connect the thrust washer with thespider. In this case, each aperture is formed by a pair of indentations232, and each pair of indentations includes one indentation from thefirst thrust washer portion 230 a and one indentation from the secondthrust washer portion 230 b. In this way, the thrust washer 230 isintended to support substantially all of the outer edges 227 of thespider gear assembly, or at least the portions of the outer edges 227that could come into contact with the housing 210.

In this embodiment, the thrust washer 230, that is, the first thrustwasher portion 230 a, and/or the second thrust washer portion 230 b, areheld/locked in place by engaging an outer diameter (OD) of at least oneof the arms 222 of the spider 220 via the indentations 232 (in thepresent embodiment, the thrust washer 230 engages all four arms 222).Each portion of the thrust washer 230 is controlled from moving axiallyinward by the interaction with the arms 222, as well as with each other.The engagement of the thrust washer 230 to the arms 222 prevents orreduces rotation of the thrust washer 230 against the housing 210. Sincethe thrust washer does not rotate against the housing, the surfaceroughness or strength of the housing 210 should not significantly affectthe wear resistance or durability of the housing 210. Further, each ofthe first thrust washer portion 230 a, and/or the second thrust washerportion 230 b are prevented from moving radially and/or axially outwardby abutting against the ID of the differential housing 210 and due tothe annular shape. In operation, the outward force of the spider gears225 pushes the thrust washer 230 outward against the housing 210, andthe housing 210 prevents separation of the portions of the thrust washer230. Examples of the orientation of axial inward and axial outwardmovement are depicted in FIG. 5A, in particular axial inward and axialoutward movement of the first thrust washer portion 230 a when the firstthrust washer portion 230 a experiences rotational forces in acounter-clockwise direction due to rotation of one of the spider gears225. Examples of the orientation of radial movement and rotation againstthe housing are depicted in FIG. 5B.

As noted above, the purpose of a thrust washer is to protect against thethrust and rotary action between the spider gear and the differentialhousing. The arrangement of the thrust washer 230 of the presentembodiment holds/locks the thrust washer 230 to the spider 220 via theindentations 232 (an engagement mechanism) while generally covering thespider gears 225 to provide protection to the housing 210.

FIG. 6 is a cross-sectional view of the differential 200 of FIG. 2 inwhich the spider gears and side gears have been removed. FIG. 6illustrates how the thrust washer 230 is constrained from moving axiallyoutward as well as radially by being placed against the ID of thehousing 210. For example, the first thrust washer portion 230 a isconstrained from moving radially by abutting against the ID of thedifferential housing 210, axially outward (to the left in FIG. 6 ) byabutting against the ID of the differential housing 210, and axiallyinward by abutting against the second thrust washer portion 230 b andthe arms 222. Likewise, the second thrust washer portion 230 b isconstrained from moving radially by abutting against the ID of thehousing 210, axially outward (to the right in FIG. 6 ) by abuttingagainst the ID of the housing 210, and axially inward by abuttingagainst the first thrust washer portion 230 a and the arms 222.

FIG. 7 is a cross-sectional perspective view of the differential 200 ofFIG. 6 in which the spider gears and side gears are hidden. FIG. 7illustrates the position of the thrust washer 230 in relation to thespider 220 when installed in the housing 210 and is intended to show howthe thrust washer 230 interacts with the spider 220 to prevent or reducerotation of the thrust washer 230 within the housing 210.

FIG. 8 is a cross-sectional view of the differential 200 of FIG. 6 ,however the spider gears 225 and side gears 215 are shown in FIG. 8 .FIG. 8 illustrates the interaction between the spider gears 225 and thethrust washer 230, in particular the position of the thrust washer 230relative to the spider gears 225 to at least partially/approximatelyenclose/cover the spider gears 225 to provide protection to the housing210.

For contrast, FIG. 9 shows a perspective cross-sectional view of aconventional thrust washer 130 in a conventional differential 100, inwhich the spider gears and side gears are removed. In this case, theconventional thrust washer 130 is engaged with a spider 120 and haslocking tabs 150 that engage with a housing 110.

FIG. 10 is a perspective view showing both a conventional washer 130 anda first portion of a thrust washer 230 a according to an embodimentherein mounted on a spider 220 to illustrate forces involved in theoperation of the differential 230. It will be understood that thisarrangement will not ordinarily be done in practice. The first portionof the thrust washer 230 a includes a plurality of indentations 232engaging the arms of the spider. The conventional thrust washer 130includes two tabs 150 on an outer diameter of the conventional thrustwasher 130 to engage a housing of a differential.

FIG. 10 shows a torque 300 applied to either the first portion of thethrust washer 230 a or the conventional thrust washer 130 due tofriction and/or rotation of the spider gear(s). If the torque 300 wereunopposed, rotation of the first portion of the thrust washer 230 a orthe conventional thrust washer 130 would result, causing wear on thehousing of the differential.

In the case of the conventional thrust washer 130, a first reactionforce 310 prevents the conventional thrust washer 130 from rotating. Inthis case, the conventional thrust washer 130 reacts to the torque 300by applying a force against the housing of the differential via the twotabs 150 while the tabs 150 act as a cantilevered beam and are subjectedto relatively high bending and contact stresses.

In the case of the first portion of the thrust washer 230 a, a secondreaction force 320 prevents the first portion of the thrust washer 230 afrom rotating. In the present embodiment, the first portion of thethrust washer 230 a is a ring/cylinder, and therefore the thrust washeris similar to a simply supported beam that is constrained on both endswhen force is applied. In this case, the thrust washer reacts to thetorque 300 by applying a force against adjacent arms of the spider whichis opposed by the second reaction force 320. Further, the secondreaction force 320 is located at a post of the spider adjacent to thegiven spider gear which is the furthest position relative to the centreof rotation of the spider gear, which minimizes the reaction force 320.The torque 300 may also be prevented from causing rotation of the firstportion of the thrust washer 230 a by a reaction force arising betweenthe housing of the differential and the first portion of the thrustwasher 230 a and/or the second portion 230 b of the thrust washer.

Due to the large moment arm between the axis of rotation of the firstportion of the thrust washer 230 a and the location of the secondreaction force 320, the force on the first portion of the thrust washer230 a is less than the force on the conventional thrust washer 130. FIG.10 also illustrates that the thrust washer described herein is supportedat multiple points as opposed to limited support points for theconventional thrust washer tab 150 (like a cantilevered beam).Alternative conventional thrust washers, such as those described herein,employing textured surfaces to reduce rotation of the conventionalthrust washer may reduce the magnitude of the reaction force 310 byspreading the reaction force across the face of the conventional thrustwasher 310, however in this case the conventional thrust washer 310 istypically capable of rotation which may cause increased wear on thehousing of the differential.

FIGS. 11A and 11B show another embodiment of a thrust washer 1130mounted in a differential 1100. Differential 1100 includes a housing1110, a spider 1120, spider gears 1125. The housing 1110 includes firsthousing portion 1110 a and second housing portion 1110 b, which may becombined to form housing 1110. FIG. 11A is a perspective view of thethrust washer 1130 mounted in the housing 1110 of the differential 1100,however spider 1120 and the spider gears 1125 have been omitted fromFIG. 11A for clarity. Differential 1100 may include side gears. Thrustwasher 1130 includes a first portion of the thrust washer 1130 a and asecond portion of the thrust washer 1130 b. Thrust washer 1130 issimilar in some ways to thrust washer 230. The thrust washer 1130 isconfigured to provide a gap 1134 between the first portion of the thrustwasher 1130 a and the second portion of the thrust washer 1130 b toallow debris (caused by, for example, wear on the spider gears or otherparts) to be removed from the sliding surface. In particular, the gap1134 can provide a channel for debris/contaminants to be removed.

A typical flow path for oil in the housing is shown in FIG. 11B. The oiltends to run up the flats on the spider inside of the spider gear.During rotation, any debris that is generated flows toward the thrustwasher 1130 due to centrifugal force. The oil will then pass over thegap 1134 allowing a pathway for debris to be removed from the areabetween the spider gears and the thrust washer. The removal of debris isintended to further reduce wear on the thrust washer and the housing.

FIG. 12 shows a further embodiment of a portion of a thrust washer 1230a. Two portions of a thrust washer 1230 a may be combined to form athrust washer similar to the description above. The portion of thethrust washer 1230 a has an annular shape and includes a plurality ofindentations 1232 and a gap 1260. The indentations 1232 are of a sizeand shape to allow the portion of a thrust washer 1230 a to engage witha spider to cover spider gears of a differential when the portion of thethrust washer 1230 a is assembled as a part of a differential. The gap1260 allows deformation of the portion of a thrust washer 1230 a toallow a shape of the portion of a thrust washer 1230 a to match a shapeof a housing of a differential and is intended to reduce hoop stress dueto manufacturing tolerances in the portion of a thrust washer 1230 aand/or a housing of a differential containing the portion of the thrustwasher 1230 a. In this case, if there is a mismatch between an outerdiameter of the thrust washer and an inner diameter of the housing, thegap 1260 may expand or collapse such that the functionality of theportion of a thrust washer 1230 a would be at least somewhat similar tothat of a continuous ring/cylinder thrust washer, for example thrustwasher 230.

Although the illustrated embodiments generally relate to a spider having4 stub shafts, one of skill in the art will understand that the spidermay have another number of stub shafts such as 2, 3, 4 or more. Theembodiments of a thrust washer described herein can be used to withstandthrust from a variety of spider gear systems. An example is shown inFIG. 13 , which illustrates a thrust washer 1330 configured for a spider1320 having three arms 1322 and a differential having three spider gears1325. In this embodiment, each half of the thrust washer (1330 a and1330 b) has three indentations 1332 that mesh to enclose the three armsof the spider 1320 (in other words, forming three connectors/aperturesto connect with the spider), while maintaining their ring/cylindricalshape.

FIG. 14 illustrates a thrust washer 1430 according to another embodimentherein, when combined with a spider and spider gears. FIG. 15 is aperspective exploded view of FIG. 14 . The thrust washer 1430 is mountedon a spider 1420 comprising two spider portions 1424. Spider gears 1425are also mounted on the spider and are generally covered by the thrustwasher 1430 to provide protection to the housing 210. Notably, in thisembodiment, thrust washer 1430 is a circular ring that includes fourapertures for receiving spider arms of the spider portions 1424, as anengagement mechanism. In this way, the thrust washer 1430 will besupported/held in position with respect to the spider 1420. Differentfrom some embodiments described herein, the thrust washer 1430 is notmade up of two or more portions.

Spider 1420 may be formed by assembling the two spider portions 1424.Each spider portion 1424 includes a groove 1426. Each groove 1426 isconfigured to allow a first groove 1426 of a first spider portion 1424to interface with a second groove 1426 from a second spider portion 1424to form the spider 1420. Each groove 1426 includes a notch 1428 to allowthe first spider portion 1424 and the second spider portion 1424 toslide past one another during assembly of the spider 1420. The spider1420 may be assembled with the spider gears 1425 generally enclosed bythe thrust washer 1430. The spider 1420 may be assembled as part of amethod of assembling a differential.

A person having ordinary skill in the art, with the benefit of thisdisclosure, will appreciate that, in alternative embodiments, a thrustwasher may be a single portion that includes a slit, gap, joint, hinge,or the like as a part of the engagement mechanism or of the thrustwasher itself to allow reversible movement of at least a portion of thethrust washer to allow assembly of the thrust washer together with thespider and spider gears. While in some embodiments of the presentdisclosure the thrust washer comprises two portions that are configuredto meet along a common circumferential surface, in alternativeembodiments the thrust washer may include portions that are of unequalsize, that are configured to mate together in alternative arrangements(e.g. overlapping segments), and may include alternative engagementmechanisms, such as aperatures/indentations of unequal size and/orshape.

A further intended advantage of the thrust washers of the presentdisclosure is that a thrust washer engages the spider arms at multiplelocations and covers all spider gears rather than providing a pluralityof conventional thrust washers.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe example embodiments. However, it will be apparent to one skilled inthe art that these specific details may not be required. In otherinstances, well-known structures may be shown in block diagram form inorder not to obscure the understanding. It will be further understoodthat, where appropriate, aspects from one embodiment may be used inother embodiments.

What has been described is merely illustrative of the application ofsome embodiments. It will be understood that elements of each embodimentmay be combined with elements of other embodiments and that not everyelement in an embodiment is required. For example, each embodiment mayinclude more or fewer elements as would be understood by one of skill inthe art on reading this description. Further, other systems, apparatusand methods can be implemented by those skilled in the art withoutdeparting from the spirit and scope of the invention, which is definedby the following claims.

We claim:
 1. A thrust washer for a differential having a housing, aspider comprising a plurality of spider arms, and one or more spidergears, the thrust washer comprising: a thrust washer body comprising anannular shape having a width configured to approximately match a widthof the one or more spider gears and further configured to a have a slopealong the width configured to conform with an inner diameter of thehousing; and at least one engagement mechanism configured to engage withat least two of the plurality of spider arms to engage the thrust washerwith the spider to approximately prevent the thrust washer from rotatingrelative to the housing when the thrust washer is installed in thedifferential.
 2. The thrust washer of claim 1, wherein the plurality ofspider arms comprises four spider arms, the at least one engagementmechanism comprises four apertures, and each of the four apertures arepositioned and oriented to engage a respective one of the four spiderarms when the thrust washer is installed in the differential.
 3. Thethrust washer of claim 1, wherein the slope along the width alsoconforms to a shape of the spider gears.
 4. The thrust washer of claim1, wherein the thrust washer body comprises a first portion and a secondportion, wherein the first portion and the second portion are connectedand configured to assemble around the spider and the spider gears. 5.The thrust washer of claim 4, wherein the slope is configured to engagewith the housing to reduce separation of the first portion and thesecond portion.
 6. The thrust washer of claims 4, wherein the firstportion and the second portion are configured to provide a gap betweenthe first portion and the second portion when assembled to allow theflow of debris or the like.
 7. The thrust washer of claim 1, wherein thethrust washer has a continuous ring shape.
 8. A differential comprising:a housing; a spider comprising a plurality of spider arms; one or morespider gears configured to be installed on the spider; at least two sidegears positioned and oriented to engage the one or more spider gearswithin the housing; and a thrust washer positioned between the housingand the at least one spider gear, the thrust washer comprising: a thrustwasher body comprising an annular shape having a width configured toapproximately match a width of the one or more spider gears and furtherconfigured to a have a slope along the width configured to conform withan inner diameter of the housing; and at least one engagement mechanismconfigured to engage with at least two of the plurality of spider armsto engage the thrust washer with the spider to approximately prevent thethrust washer from rotating relative to the housing when the thrustwasher is installed in the differential.
 9. The differential of claim 8,wherein the plurality of spider arms comprises four spider arms, the atleast one engagement mechanism comprises four apertures, and whereineach of the four apertures are positioned and oriented to engage arespective one of the four spider arms when the thrust washer isinstalled in the differential.
 10. The differential of claim 8, whereinthe slope along the width also conforms to a shape of the spider gears.11. The differential of claim 8, wherein the thrust washer comprises afirst portion and a second portion, wherein the first portion and thesecond portion are connected and configured to assemble around thespider and the spider gears.
 12. The differential of claim 11, whereinthe slope is configured to engage with the housing to reduce separationof the first portion and the second portion.
 13. The differential ofclaim 11, wherein the first portion and the second portion areconfigured to provide a gap between the first portion and the secondportion to allow the flow of debris or the like.
 14. The differential ofclaim 8, wherein the thrust washer has a continuous ring shape.